The present invention relates to firearms, and in particular to firearms employing percussive caps to ignite a propellent charge.
The percussion firing system was developed early in the 19th century to replace the flintlock method for igniting a propellent charge in a firearm. The basic elements of this system are a percussive firing cap and a nipple communicating with the firearm ignition chamber. The firing cap is designed to fit snugly over the nipple in a position to be struck by the firearm's hammer. When struck, an explosive fulminate in the base of the cap produces a quantity of burning gas in the nipple, and this gas is forced under considerable pressure into the ignition chamber of the firearm, igniting the propellent charge therein.
The above-described nipple has not been entirely satisfactory, in that heated gases from the detonated firing cap tend to blow back in the direction of the cap. Such blow-back adversely affects ignition efficiency, and may present a danger to the firearm user. Blow-back of heated gases may also occur upon ignition of the propellent charge within the firearm ignition chamber, also diminishing the firearm performance.
In the present invention, there is provided a novel nipple in which blow-back of heated gases is controlled so as to reduce the danger to the firearm user and increase the efficiency of ignition of the propellent charge within the gun. The nipple of the present invention includes an elongate body having, adjacent one end, a cap-receiving portion, and adjacent the opposite end, a mounting portion which is used in mounting the nipple on the firearm. An elongate firing chamber extends axially into the nipple through the cap-receiving portion. The outer surface of the cap-receiving portion is dimensioned to receive a firing cap thereon, with the sides of the firing cap closely confronting such surface. A pair of diametrically opposed ports extend between and open to the chamber and to locations on the surface of the cap-receiving portion, which portions are covered by the cap when the latter is received thereon.
Upon ignition of the firing cap, a portion of the pressurized gases within the firing chamber is released through the two port openings, this release tending to deform the sides, or skirt of the firing cap. The energy of the blow-back gases is dissipated principally in the deformation of the firing cap sides, rather than in the blow-back of the cap toward the firearm user. Venting of gases through the nipple port openings during cap firing prevents a discontinuity in the nipple gas pressure, producing a more constant injection of heated gas particles into the firearm ignition chamber.
It is a principal object of the present invention to provide, for use in a firearm of the type employing a percussive firing cap, a nipple which permits release of blow-back gases through side portions thereof.
Another important object of the invention is to provide such a nipple constructed to effect a more even, controlled flow of pressurized gases from the nipple into the ignition chamber of a firearm.
It is yet another object of the invention to provide an improved nipple which may be easily constructed from known, preexisting firearm nipples.
These and other objects and features of the present invention will become more fully apparent when read in relation to the following detailed description of the preferred embodiment of the invention and the accompanying drawings.